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<a name="ecvt"></a>
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<div class="header">
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<p>
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Next: <a href="gcvt.html#gcvt" accesskey="n" rel="next">gcvt</a>, Previous: <a href="div.html#div" accesskey="p" rel="prev">div</a>, Up: <a href="Stdlib.html#Stdlib" accesskey="u" rel="up">Stdlib</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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<a name="ecvt_002c-ecvtf_002c-fcvt_002c-fcvtf_002d_002d_002ddouble-or-float-to-string"></a>
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<h3 class="section">2.13 <code>ecvt</code>, <code>ecvtf</code>, <code>fcvt</code>, <code>fcvtf</code>—double or float to string</h3>
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<a name="index-ecvt"></a>
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<a name="index-ecvtf"></a>
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<a name="index-fcvt"></a>
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<a name="index-fcvtf"></a>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">#include <stdlib.h>
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char *ecvt(double <var>val</var>, int <var>chars</var>, int *<var>decpt</var>, int *<var>sgn</var>);
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char *ecvtf(float <var>val</var>, int <var>chars</var>, int *<var>decpt</var>, int *<var>sgn</var>);
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char *fcvt(double <var>val</var>, int <var>decimals</var>,
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int *<var>decpt</var>, int *<var>sgn</var>);
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char *fcvtf(float <var>val</var>, int <var>decimals</var>,
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int *<var>decpt</var>, int *<var>sgn</var>);
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</pre></div>
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<p><strong>Description</strong><br>
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<code>ecvt</code> and <code>fcvt</code> produce (null-terminated) strings of digits
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representating the <code>double</code> number <var>val</var>.
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<code>ecvtf</code> and <code>fcvtf</code> produce the corresponding character
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representations of <code>float</code> numbers.
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</p>
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<p>(The <code>stdlib</code> functions <code>ecvtbuf</code> and <code>fcvtbuf</code> are reentrant
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versions of <code>ecvt</code> and <code>fcvt</code>.)
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</p>
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<p>The only difference between <code>ecvt</code> and <code>fcvt</code> is the
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interpretation of the second argument (<var>chars</var> or <var>decimals</var>).
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For <code>ecvt</code>, the second argument <var>chars</var> specifies the total number
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of characters to write (which is also the number of significant digits
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in the formatted string, since these two functions write only digits).
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For <code>fcvt</code>, the second argument <var>decimals</var> specifies the number of
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characters to write after the decimal point; all digits for the integer
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part of <var>val</var> are always included.
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</p>
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<p>Since <code>ecvt</code> and <code>fcvt</code> write only digits in the output string,
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they record the location of the decimal point in <code>*<var>decpt</var></code>, and
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the sign of the number in <code>*<var>sgn</var></code>. After formatting a number,
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<code>*<var>decpt</var></code> contains the number of digits to the left of the
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decimal point. <code>*<var>sgn</var></code> contains <code>0</code> if the number is positive,
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and <code>1</code> if it is negative.
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</p>
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<br>
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<p><strong>Returns</strong><br>
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All four functions return a pointer to the new string containing a
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character representation of <var>val</var>.
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</p>
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<br>
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<p><strong>Portability</strong><br>
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None of these functions are ANSI C.
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</p>
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<p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>,
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<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>.
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</p>
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<br>
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<br>
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<hr>
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<div class="header">
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<p>
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Next: <a href="gcvt.html#gcvt" accesskey="n" rel="next">gcvt</a>, Previous: <a href="div.html#div" accesskey="p" rel="prev">div</a>, Up: <a href="Stdlib.html#Stdlib" accesskey="u" rel="up">Stdlib</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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